This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Structural magnetic resonance imaging (MRI) and positron emission tomography (PET) studies were conducted examining neuroanatomical and neurophysiological correlates of behavioral lateralization. Using voxel-based morphology, we have found that apes show left hemisphere asymmetries in the frontal operculum and posterior temporal lobe for gray matter. Using PET, we have found that vocal and gestural communication is associated with activity in several important brain areas including the frontal operculum, caudate and cingulate gyrus. We have also found that chimpanzees show pronounced right hemisphere activation in the processing of species-specific sounds.